Adapter to use small, square-ended bits

Our braces have, at the base of the chuck, a square hole to accept and hold fast the square shaft-ends of bits designed for this type of tool. The hole is sized to accept the most common sizes of square shafted bits. But there are a variety of bits out there whose shaft ends are too small to be held fast in the 8 x 8 mm hole. If one attempts to use these smaller bits, they will only be held by the four jaws and can turn or come loose under torque in use. So we offer this small adapter, made of a section of square brass tube, which reduces the hole in the base of the chuck from 8 x 8 mm to 6 x 6 mm, just right for many smaller bits.

Small and simple, but it works great! This inexpensive adapter allows you to use a far wider range of bits in your brace!

This is the four-jawed chuck on our brace.

After you unscrew and remove the housing, you can see the four jaws, and under them the four-sided hole to accept square-ended shafts.

The four jaws mostly serve to center the bit.

The square hole at the base keeps the bit from turning in use. In our chuck the square hole is 8 x 8 mm by 15 mm deep.

Large- and medium-sized square-ended bits are held firmly by the hole.

But smaller bits can turn and shift off center. We can unfortunately not say with certainty which bits will work and which will not in our braces, as the manufacturing tolerances for the ends of these kinds of bits are very loose. And of course there is often a wide variation among different users as to what they find acceptable and what they don’t.

Here you see the same bit held firmly in place by our adapter. Perfect fit! We highly recommend that you order this inexpensive little tool when ordering a brace and sets of bits. Then you will be absolutely sure that you can use the widest variety of bits possible with this tool.

The adapter is 18 mm long, while the hole is 15 mm deep. This leaves 3 mm projecting out of the hole. In the event that the adapter becomes stuck, it can be easily gripped and pulled out with a set of pliers.

To use the adapter, it is not necessary to remove the housing every time. In the photo you can see that it is possible to simply press the adapter, straight and firmly, onto the end of the bit, and then the two can be inserted normally into the brace’s chuck.

Idea: If you only use smaller-sized bits, you can glue the adapter in place.